Optimal waiting period for fresh embryo transfer after hysteroscopic adhesiolysis: a retrospective cohort study

BACKGROUND: Very few studies have been conducted regarding the optimal time interval between hysteroscopic adhesiolysis and the embryo transfer (ET). Investigation of this optimal time may be helpful for assisted reproductive technology. Therefore, we investigated effects of the interval between hysteroscopic adhesiolysis and ET upon in vitro fertilization (IVF) cycle outcomes. METHODS: Patients were recruited between January 2014 and September 2017 at the Reproductive Hospital Affiliated to Shandong University. Patients who were diagnosed with intra-uterine adhesion (IUA) and underwent hysteroscopic adhesiolysis before fresh IVF-ET or intra-cytoplasmic sperm injection cycles were classified into three groups according to the interval between hysteroscopic adhesiolysis and ET: less than 90 days (Group 1), 90 to 180 days (Group 2), and greater than 180 days (Group 3). Baseline characteristics, controlled ovarian stimulation (COS) response, and pregnancy outcomes after ET were compared. Analysis of variance or non-parametric tests were used to test numerical data. The Pearson's Chi-squared test was used to test categorical data. RESULTS: A total of 312 patients were recruited as follows: 112 in Group 1, 137 in Group 2, and 63 in Group 3. There were no differences in baseline and COS characteristics among the three groups. The live-birth rate in Group 2 (40.1%) was significantly higher than that in Group 1 (17.9%; χ(2) = 14.545, P < 0.001). There were no significant differences in the rates of biochemical, ongoing, and clinical pregnancy, and biochemical and clinical pregnancy abortion, as well as stillbirth among the groups. In the mild IUA patients, the live-birth rate was significantly higher in Group 2 (42.6%) compared with Group 1 (22%; χ(2) = 8.413, P = 0.004). In the moderate IUA patients, Group 2 (35.7%) had a higher frequency of live births than Group 1 (6.7%; χ(2) = 8.187, P = 0.004). CONCLUSIONS: The optimal waiting period for fresh ET after hysteroscopic adhesiolysis was 90 to 180 days in the current study.